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Project Dates

April 27, 1998 to April 30, 1998

Project Description

This case follows the evolution of a low pressure system through its life cycle as it moved from Arkansas to Illinois, and provides a good example of the effects of model biases in the AVN model. The errors introduced to the AVN model due to inherent biases resulted in an incorrect prediction of strong cyclogenesis over the Gulf of Mexico.

Objectives

This case was developed for the COMAP Symposium on Numerical Weather Prediction to show the biases and systematic errors seen in the operational version of the AVN and MRF global models.

Data Access for COMET Case 015

Project Dates

May 30, 1998 to June 1, 1998

Project Description

Case 018 is the latest in a series of convective cases from different regions of the United States. This case focuses on the tornado that hit Spencer, SD and a long lived derecho event that moved from MN to NY.

Objectives

This case has been studied by various NWS offices and has been presented at numerous workshops and conferences.

Data Access for COMET Case Study 018

Project Dates

June 2, 1998 to June 3, 1998

Project Description

Case 022 focuses on the event that brought severe weather from Buffalo, NY to Sterling, VA. This case is temporally connected to COMET Case 018 as it follows the derecho event that moved from Minnesota to New York. Initial research has indicated that COMET Case 022 has possible vorticity connections asssociated with the severe weather outbreak highlighted in COMET Case 018.

Objectives

This case provides an example of severe weather experienced by the Northeastern United States.

Data Access for COMET Case Study 022

Project Dates

June 29, 1998 to June 30, 1998

Project Location

Iowa

Project Description

On June 29th, 1998, a MCS evolved from a supercell thunder- storm as it crossed Iowa. This bow echo, with its associated derecho, produced very strong straight line winds, hail, and numerous tornados, microbursts, and flooding. The bow echo finally merged with a squall line and slowly weakened later in the evening.

Objectives

This case expands our coverage of Mesoscale Convective Systems, and provides an opportunity to study the evolution of a bow echo and its associated derecho from initial convection to dissipation

Data Access for COMET Case Study 039

Project Dates

September 2, 1998 to September 3, 1998

Project Description

On 2 September 1998, a series of strong thunderstorms affected southern California, bringing strong winds, lightning and heavy rains. The winds knocked down power line and trees across the area, while the heavy rains resulted in widespread flash flooding across the valley. In addition,a funnel cloud was reported by a helicopter pilot near Pomona, CA. Lightning strikes also started several wildfires, the largest fire consumed 1,500 acres of grass east of Bakersfield.

Objectives

This case expands our severe weather coverage to southern California and allows an in-depth study of dynamics producing the these conditions.

Data Access for COMET Case Study 041

Project Dates

October 4, 1998 to October 5, 1998

Project Description

The Kansas city flood hit the afternoon and evening of October 4, 1998. Parts of the metropolitan area received almost eight inches of rain that day with some locations hit by a five-inch deluge in one hour. The downpours resulted in considerable flash flooding, 12 deaths, and millions of dollars in damage.

Objectives

This case provides an example of an urban flash flood.

Data Access for COMET Case Study 040

Project Dates

October 16, 1998 to October 19, 1998

Project Description

During the weekend of 17-18 October 1998, heavy rains fell over south and southeast Texas. Low level moisture was transported into southeast Texas from the Gulf of mexico while Hurricane Madeline off the Pacific coast of Mexico provided mid-level moisture into southern Texas. 20 to 30 inches of rain fell locally near San Antonio, with surrounding areas receiving 10 to 20 inches of precipitation. This heavy rainfall resulted in flash flooding from San Antonio to Austin, followed by record breaking river flooding along several southern Texas rivers in the following days. 31 people drowned during the flooding.

Objectives

This case provides an example of a flash flooding scenario.

Data Access for COMET Case Study 035

Project Dates

October 30, 1998 to November 1, 1998

Project Description

Case 021 focuses on the 11 inch rainfall in south-central Kansas which caused four main rivers to experience record flooding. There were numerous incidents of flash flooding which closed roads and resulted in one automobile-related fatality.

Objectives

This case provides data from this flooding event to allow more in depth study of the flood event.

Data Access for COMET Case Study 021

Project Dates

November 8, 1998 to November 11, 1998

Project Description

Case 023 follows the development of a strong extratropical cyclone that took place from 8-11 November 1998. Severe weather that accompanied the case included blizzard conditions in the Upper Midwest and severe thunderstorms over the Mississippi Valley

Objectives

The case allows the study of extratropical cyclone development from initial to mature stages.

Data Access for COMET Case Study 023

Project Dates

January 1, 1999 to January 2, 1999

Project Description

On 1-2 January 1999, southeast Texas and southwest Louisiana experienced a major tornado outbreak which featured 1 F3, 5 F2's, and 8 F0-F1's. While southern Louisiana's annual average for tornados is 13 (1950-1995), it hosted 12 tornados on 1-2 January. All of the tornados were indicated by WSR-88D radars in Lake Charles and Fort Polk, Louisiana. The average lead time was an impressive 24 minutes. There was one fatality in Texas, but, given the severity of the outbreak and the fact that it happened overnight, it is fortunate that there were not more people injured or killed.

Objectives

This case expands our coverage of severe weather to Texas and Louisiana, and allows study of a major severe weather outbreak along the Gulf Coast in January.

Data Access for COMET Case Study 027